Silicone-based septum is faced on one side with a double layer of polyimide and PTFE. The polyimide adheres to both the silicone and PTFE, providing a better bond and enhanced durability. The outer PTFE coating assures maximum inertness and helps minimize bleed. Maximum inlet temperature 225 deg. C. Packaged in Plastic Bag: 4 in. x 6 in.; weight: 8.5 g.